This invention relates to a mechanism, which is useful as a slip clutch sometimes-termed torque limiters, and also useful as a holding device or brake and a method of making the same.
Slip clutch mechanisms of various constructions are used in many applications to couple a driving shaft to a driven shaft or other device, and to limit the transmitted torque. They may also be used in or as hinges to hold one device in a predetermined angular position with respect to another device, for example, the lid of a case for a laptop computer. In the latter type of uses the slip clutches provide the function of brakes.
The prior art discloses many different slip clutch constructions using various spring arrangements to establish a slip torque between a driving and driven member to thereby limit the torque transmitted.
Some of these prior art devices are relatively complicated, requiring a large number of parts and helical springs and most are limited in the slip torque range they can provide. Also, there is a constant demand of organizations using small slip clutches for a more economical device.
The present invention provides a new and improved slip clutch construction which uses a minimal number of different parts, which construction permits a wide range of slip torques and which is simplified in manufacture. The invention also provides a slip clutch having the above characteristics which is bi-directional in operation.
An object of this invention is to provide a new and improved mechanism for slip clutch or brake design and construction and which permits a wide range of slip torques for a given size clutch and a wide range of holding forces when used as a brake.
Another object of this invention is to provide a new and improved mechanism for a slip clutch with a more easily controllable and repeatable slip torque, which is less susceptible to wear.
Another object of this invention is to provide a new and improved slip clutch, which utilizes a minimum number of different parts and is easy to assemble.
A further object of this invention is to provide a new and improved method of making a mechanism of the type described having the foregoing characteristics.
A still further object of this invention is to provide a new and improved mechanism of the type described which provides a wide range of design choices and method of making the same.
Briefly stated, the invention, in one form thereof, comprises a slip clutch which comprises only three different components, a first hollow cylindrical member having an inner wall, a second generally cylindrical member received coaxial within the first member and at least one third member between the first and second members and having frictional engagement with the inner wall of the first member. The second member has a longitudinal recess in the form of a flat or defined by angularly spaced apart walls on radii from the longitudinal axis of the second member The at least one third member is generally annular has its ends bent inwardly and forming arms extending into the recess and arranged to be contacted by or contact one of the recess defining walls. Upon rotation of the first member as a driving member, the second member is driven through the frictional contact of the third member with the inner wall and the arms of the at least one third member acting on the recess defining walls. When the second member is rotated as a driving member, a recess-defining wall contacts an arm of the third member and drives the first member through the frictional contact of the third member therewith.
The invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, together with further objects and advantages thereof may be best appreciated by reference to the following detailed description taken in conjunction with the drawings.